Beverage preparation machines are well known in the food science and consumer goods area. Such machines allow a consumer to prepare at home a given type of beverage, for instance a coffee-based beverage, e.g. an espresso or a brew-like coffee cup.
Today, most beverage preparation machines for in-home beverage preparation comprise a system made of a machine which can accommodate portioned ingredients for the preparation of the beverage. Such portions can be soft pods or pads, or sachets, but more and more systems use semi-rigid or rigid portions such as rigid pods or capsules. In the following, it will be considered that the beverage machine of the invention is a beverage preparation machine working a rigid capsule.
The machine comprises a body and dispensing head attached to said body. The dispensing head comprises a receptacle for accommodating said capsule. A fluid injection system is disposed inside the machine head, for injecting a fluid—preferably water—under pressure into said capsule. Water injected under pressure in the capsule, for the preparation of a coffee beverage according to the present invention, is preferably hot, that is to say at a temperature above 70° C. However, in some particular instances, it might also be at ambient temperature. The pressure inside the capsule chamber during extraction and/or dissolution of the capsule contents is typically about 1 to 6 bar for dissolution products, 2 to 12 bar for extraction of roast and ground coffee. Such a preparation process differs a lot from the so-called “brewing” process of beverage preparation—particularly for tea and coffee, in that brewing involves a long time of infusion of the ingredient by a fluid (e.g. hot water), whereas the beverage preparation process allows a consumer to prepare a beverage, for instance coffee within a few seconds.
The principle of extracting, infusing, and/or dissolving the contents of a closed capsule under pressure is known and consists typically of confining the capsule in a receptacle of a machine, injecting a quantity of pressurized water into the capsule, generally after piercing a face of the capsule with a piercing injection element such as a fluid injection needle mounted on the machine, so as to create a pressurized environment inside the capsule either to extract the substance or dissolve it, and then release the extracted substance or the dissolved substance through the capsule. Capsules allowing the application of this principle have already been described for example in applicant's European patent no EP 1 472 156 B1, and in EP 1 784 344 B1.
Machines allowing the application of this principle have already been described for example in patents CH 605 293 and EP 242 556. According to these documents, the machine comprises a receptacle for the capsule and a perforation and injection element made in the form of a hollow needle comprising in its distal region one or more liquid injection orifices. The needle has a dual function in that it opens the top portion of the capsule on the one hand, and that it forms the water inlet channel into the capsule on the other hand.
The machine further comprises a fluid tank—in most cases this fluid is water—for storing the fluid that is used to dissolve and/or infuse and/or extract under pressure the ingredient(s) contained in the capsule. The machine comprises a heating element such as a boiler or a heat exchanger, which is able to warm up the water used therein to working temperatures (classically temperatures up to 80-90° C.). Finally, the machine comprises a pump element for circulating the water from the tank to the capsule, optionally though the heating element. Fluid tank, heating element, pump element, are usually located within the machine body, and are linked to the dispensing head with a fluid circuit.
The way the water circulates within the machine is selected via a selecting valve means, such as for instance a peristaltic valve of the type described in applicant's European patent application EP 2162653 A1.
When the beverage to be prepared is coffee, one interesting way to prepare the said coffee is to provide the consumer with a capsule containing roast and ground coffee powder, which is to be extracted with hot water injected therein.
Capsules have been developed for such an application, which are described and claimed in applicant's European patent EP 1 784 344 B1, or in European patent application EP 2 062 831.
In short, such capsules comprise typically:                a hollow body and an injection wall which is impermeable to liquids and to air and which is attached to the body and adapted to be punctured by e.g. an injection needle of the machine,        a chamber containing a bed of roast and ground coffee to be extracted,        an aluminum membrane disposed at the bottom end of the capsule, closing the said capsule, for retaining the internal pressure in the chamber, the said membrane being associated with piercing means for piercing dispensing holes in the said aluminum membrane when said internal pressure inside the chamber reaches a certain predetermined value,        optionally, means configured to break the jet of fluid so as to reduce the speed of the jet of fluid injected into the capsule and distribute the fluid across the bed of substance at a reduced speed.        
Beverage preparation machines and capsules as described above, for many of them, are designed to give the consumer the choice of preparing the beverage he likes amongst a whole range of beverage products.
In the range of beverages that is proposed to the consumer, some correspond to large cups typically having a volume of 200 ml or above, for instance Caffee Crema Grande, latte macchiatos, cappuccinos, chococinos, American brew-like coffees, or the like. Some other beverages correspond to mid-size cups typically between 100 and 200 ml, like for instance teas, herbal infusions, Chai tea, tea latte, or chocolate-based preparations such as Nesquik®. Finally, some correspond to small serving size, typically below 100 ml, such as for instance espressos, ristretto, or cortado coffee.
Due to the fact that the range of product recipes can be wide, that is available for preparation with the same type of machine, and the therefore that the volume to be dispensed can vary from one beverage to another, a constant issue with known machines is that the distance between the cup tray (or drip tray) and the beverage dispensing outlet of the extraction head is often not adapted to the cup size that is chosen by the consumer. Particularly, this distance is often too large. As a result, beverage liquid may splash during dispensing, which is of course undesirable. In order to solve the splashing issue, most machines are equipped with a cup/drip tray that is adjustable in height. Height position of the tray may be continuous, or be a step-by-step mechanism. However, in all known systems, handling and setting of the cup tray is uneasy, and certainly, user-friendliness of such systems can be improved. Moreover cup trays which are adjustable in height often show stability problems, which is of course undesirable.
WO 2006/127108 A2 discloses an extraction head that is movable relative to the cup tray. The movement of the dispensing head is performed along a linear, vertical axis of the machine body. Guiding means allow to keep the movement along a straight direction. While the machine disclosed in this application contains interesting features, the movement of the dispensing head is limited to a single degree of liberty, i.e. to a vertical, up and down movement.
However, one essential requirement in beverage preparation machines, and particularly if the dispensing head is movable relative to the machine body, is that leakage be prevented in the dispensing head during injection of water, as well as backflow splashing of liquid present in the capsule after dispensing. Backflow is well disclosed in applicant's European patent EP 1967100 B1, wherein a system is described and claimed, that was developed to ensure that backflow does not occur, and that the capsule is positioned at a certain predetermined angle relative to the injection system of the machine. This prevents that liquid level in the capsule during or after beverage preparation be such as to be in contact with the zone of the capsule's top membrane which is pierced by the fluid injection system of the machine, which would create a sucking effect and therefore a backflow when said capsule still contains pressurized liquid and the fluid injection system is removed from the top membrane.
There is a need for a beverage preparation machine comprising a dispensing head with beverage outlet that is movable relative to the machine body along a non-linear path, while guaranteeing that no backflow or leakage occurs, whatever the position of the dispensing head.